Field of the Invention
The present invention relates to polymer-derived ceramics, precursors, and methods of using and making the same.
Description of Related Art
Polymer-derived ceramics, such as silicon carbide (SiC), siliconoxycarbide (SiOC), silicon carbonitride (SiCN), aluminum nitride (AlN), and hafnium carbide (HfC), can be synthesized by thermal decomposition of suitable polymeric precursors, and possess some remarkable properties, such as high oxidation resistance, high temperature piezoresistivity, high mechanical strength, and photoluminescence.
The future success of battery operated vehicles and portable electronic devices will require invention of lightweight, safer, high capacity, long lasting and high power electric sources. From a practical standpoint, advanced lithium ion battery technology (a-LIB) seems to be the most viable option. Therefore, considerable improvements to the present-day LIB electrode and electrolyte materials and design are needed to achieve high rate capability, short charging time, high energy density, and long cycle life. Accordingly, much of the research emphasis has been on the development of high capacity anode materials; particularly silicon anodes because of its high theoretical lithium discharge capacity of 3850 mAh·g−1 (>10 times that of commercial graphite). Traditional silicon however has other shortcomings such as low electrical conductivity, large volumetric changes that cause cracking, and unstable solid electrolyte interphase (SEI) formation that leads to poor C-rate and capacity fading. Consequently, several silicon nanostructured electrode design and 3-D assemblies involving shell/core nanowires, nanorods, microspheres and particles etc. have been proposed and fabricated. These new designs have considerably alleviated many of the issues, however, the relatively low volumetric energy densities and challenges associated with their large-scale production and high manufacturing cost must be overcome before such technologies can be commercialized.